(a) Field of the Invention
The present invention relates to a golf clubhead of so-called "metal wood golf club head," from No. 1 to No. 3, etc., and its manufacturing method.
(b) Description of Prior Art
Golf clubheads called "metal wood golf club heads" have heretofore been manufactured by a lost wax process, i.e., a process of pouring melted metal into a casting mould obtained by removing an original wax die attached thereto. Conventional lost wax process admittedly made make it possible to precisely mould each surface of a golf clubhead, but it still does not permit varying each thickness of each surface thereof to a great degree.
It is well known that lowering the center of gravity of a golf clubhead allows balls to be hit farther. In accordance with conventional lost wax process, however, it is impossible to lower the center of gravity to a large degree or by a great amount, because it does not permit varying each thickness of each surface of a golf clubhead in a large measure as described above. Consequently, the distance between a face inclined at a predetermined loft angle and the center of gravity of a golf clubhead can not be sufficiently elongated, so that what is called "sweet area" or "sweet spot" on the face cannot be enlarged further.